I was saying two things.... 1. yes you can make an X out of straight pieces, but unless the exhaust under you're truck is running at 45 degree angles you'll need elbows to turn the pipe and actually hook it into something. By the time you add up all the pieces you'll find that those pre-made ones aren't very expensive at all..... 2. Its not a matter of sharp edges, you'll have those in most cases unless its a stamped piece like Magnaflow makes. Its a matter of area inside the pipe and of what you are actually trying to do with the X. Two straight pipe made into an X will have a cross section at the smallest point that is not much bigger than one pipe by itself. Thats restrictive. When you take curved pieces and make them into an X you don't cut halfway into each one (the narrowest part would again be the same area as one pipe) you only cut away part of each one so flow from the two sides can blend together. The idea isn't to have all the exhaust from one side go down the opposite pipe after the X, its just to merge them to smooth out the pulses from the different cylinder banks.